665775778 has 8 divisors (see below), whose sum is σ = 1030878720. Its totient is φ = 322149540.

The previous prime is 665775757. The next prime is 665775787. The reversal of 665775778 is 877577566.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5369098 + ... + 5369221.

It is an arithmetic number, because the mean of its divisors is an integer number (128859840).

Almost surely, 2^665775778 is an apocalyptic number.

665775778 is a deficient number, since it is larger than the sum of its proper divisors (365102942).

665775778 is a wasteful number, since it uses less digits than its factorization.

665775778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10738352.

The product of its digits is 17287200, while the sum is 58.

The square root of 665775778 is about 25802.6312224161. The cubic root of 665775778 is about 873.1911598034.

The spelling of 665775778 in words is "six hundred sixty-five million, seven hundred seventy-five thousand, seven hundred seventy-eight".